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Earth: Rotation Variation & Resulting Timekeeping Adjustments
- Thread starter Mighty_Emperor
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as in relativity the faster you go the slower time gets would this mean that our present time is in fact becomeing faster?
Relatively speaking, time has become faster, but it's not of cosmological consequence. It just means the coming days will be longer than the previous days.
The moon is also slowing us down btw, and the length of a day has grown by about half a minute in the past half century. The earth will keep slowing down until it reaches an equillibrium of some sort. Provided it isn't destroyed by then.
The moon is also slowing us down btw, and the length of a day has grown by about half a minute in the past half century. The earth will keep slowing down until it reaches an equillibrium of some sort. Provided it isn't destroyed by then.
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Anonymous
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so our distant history was far closer than they say.
as the years were shorter.
as the years were shorter.
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I recall reading somewhere (source unknown, as per bloody usual), that the moon acts as a brake on the rotation of the earth, gradually slowing it down. This continues until the earth has slowed enough to lower its gravitational field, releasing the moon. As the moon retreats from the earth, the braking effect is lessened, allowing the earth to speed up again, increasing its gravitational field, pulling the moon towards the earth, which acts as a brake...The Frog said:...The moon is also slowing us down btw, and the length of a day has grown by about half a minute in the past half century. The earth will keep slowing down until it reaches an equillibrium of some sort. Provided it isn't destroyed by then.
Please note: I heard this theory when I was but a sprog, it may be much more technical than I've shown it here
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Calls to scrap the 'leap second' grow
17 December 2008 by Devin Powell
AT MIDNIGHT on New Year's Eve, time will stop momentarily. Guardians of atomic clocks around the world will add an extra "leap second" to 2008 to keep time synched with the Earth's rotation. Arguably, the rise of GPS makes this tweak unnecessary.
In 1972, global commerce began to set its clocks by Coordinated Universal Time (UTC), based on the oscillations of the caesium atom. The snag was that other things, such as shipping and aircraft navigation, still relied on UT1 time, which divides one rotation of the Earth into 86,400 seconds. But the Earth's spin is slowing, so the two systems gradually go out of synch. "Over the course of a millennium, the differences would accumulate to about an hour," says Robert Nelson of the Satellite Engineering Research Corporation in Bethesda, Maryland.
To compensate, the ITU, or International Telecommunications Union, adds a leap second to atomic time every few years. However, many argue that we should stop tinkering with time, not least because of the glitches it causes (see "Add second...").
Now a group within the ITU, called Working Party 7A - after deliberating over the leap second for years - has told New Scientist that it recommends abolishing the leap second. Group member Elisa Felicitas Arias, of the International Bureau of Weights and Measures in Paris, France, argues that a timescale that doesn't need regular tweaking is essential in an increasingly interconnected world. What's more, she says, ships and aircraft now navigate via GPS rather than the old time system. GPS runs on a version of atomic time.
Next year, member states of the ITU are due to vote on the proposal. If 70 per cent support the idea, an official decision will be made at the World Radio Conference in 2011. According to a report co-authored by Felicitas Arias, most member states support the idea. The UK, however, is against reworking its laws, which include the solar timescale Greenwich Mean Time. Without the UK abolition may be difficult, says Felicitas Arias.
Astronomers are also uneasy with cutting clocks off from the sun. However, a recent survey conducted by the American Astronomy Society showed that their research would be little affected. Stargazing software can handle the new time system, says Jim Ulvestad of the National Radio Astronomy Observatory in Charlottesville, Virginia.
If the leap second is removed, most people won't notice. Some adjustment to atomic time may be needed eventually though, otherwise our descendants will experience sunrise at completely different times of day to us.
Add second and wait for blackouts
"In theory, adding a second is as easy as flipping a switch; in practice, it rarely works that way," says Dennis McCarthy of the US Naval Research Laboratory, which provides the time standard used by the US military.Most likely to be affected are IT systems that need precision of less than a second. In 1998 - two leap seconds ago - cellphone communications blacked out over part of the southern US. Different regions of service had slipped into slightly different times, preventing proper relaying of signals. Judah Levine of the National Institute of Standards and Technology in Boulder, Colorado, which provides the time standard and technical support for most commercial activities in the US is braced for New Year's Eve. "On December 31, I'll be waiting with a cup of coffee for the problems to roll in," he sighs.
http://www.newscientist.com/article/mg2 ... -grow.html
17 December 2008 by Devin Powell
AT MIDNIGHT on New Year's Eve, time will stop momentarily. Guardians of atomic clocks around the world will add an extra "leap second" to 2008 to keep time synched with the Earth's rotation. Arguably, the rise of GPS makes this tweak unnecessary.
In 1972, global commerce began to set its clocks by Coordinated Universal Time (UTC), based on the oscillations of the caesium atom. The snag was that other things, such as shipping and aircraft navigation, still relied on UT1 time, which divides one rotation of the Earth into 86,400 seconds. But the Earth's spin is slowing, so the two systems gradually go out of synch. "Over the course of a millennium, the differences would accumulate to about an hour," says Robert Nelson of the Satellite Engineering Research Corporation in Bethesda, Maryland.
To compensate, the ITU, or International Telecommunications Union, adds a leap second to atomic time every few years. However, many argue that we should stop tinkering with time, not least because of the glitches it causes (see "Add second...").
Now a group within the ITU, called Working Party 7A - after deliberating over the leap second for years - has told New Scientist that it recommends abolishing the leap second. Group member Elisa Felicitas Arias, of the International Bureau of Weights and Measures in Paris, France, argues that a timescale that doesn't need regular tweaking is essential in an increasingly interconnected world. What's more, she says, ships and aircraft now navigate via GPS rather than the old time system. GPS runs on a version of atomic time.
Next year, member states of the ITU are due to vote on the proposal. If 70 per cent support the idea, an official decision will be made at the World Radio Conference in 2011. According to a report co-authored by Felicitas Arias, most member states support the idea. The UK, however, is against reworking its laws, which include the solar timescale Greenwich Mean Time. Without the UK abolition may be difficult, says Felicitas Arias.
Astronomers are also uneasy with cutting clocks off from the sun. However, a recent survey conducted by the American Astronomy Society showed that their research would be little affected. Stargazing software can handle the new time system, says Jim Ulvestad of the National Radio Astronomy Observatory in Charlottesville, Virginia.
If the leap second is removed, most people won't notice. Some adjustment to atomic time may be needed eventually though, otherwise our descendants will experience sunrise at completely different times of day to us.
Add second and wait for blackouts
"In theory, adding a second is as easy as flipping a switch; in practice, it rarely works that way," says Dennis McCarthy of the US Naval Research Laboratory, which provides the time standard used by the US military.Most likely to be affected are IT systems that need precision of less than a second. In 1998 - two leap seconds ago - cellphone communications blacked out over part of the southern US. Different regions of service had slipped into slightly different times, preventing proper relaying of signals. Judah Levine of the National Institute of Standards and Technology in Boulder, Colorado, which provides the time standard and technical support for most commercial activities in the US is braced for New Year's Eve. "On December 31, I'll be waiting with a cup of coffee for the problems to roll in," he sighs.
http://www.newscientist.com/article/mg2 ... -grow.html
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Days, hours, minutes and seconds all originally derived from the Earth's rotation. But this rotation is slowing down (something we can measure with atomic clocks) so everyday clocks need occassional adjustments to allow for this fact.
This page, About Leap Seconds http://www.timeanddate.com/time/leapseconds.html
explains how this works:
But atomic clocks are still our most precise time measurers.
This page, About Leap Seconds http://www.timeanddate.com/time/leapseconds.html
explains how this works:
This system keeps the old familiar style of timekeeping, but corrects it as necessary to match the actual movements of the Earth.
(For more detail, see http://en.wikipedia.org/wiki/Leap_second )
But atomic clocks are still our most precise time measurers.
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Here we go again...
Clocks to read 11:59:60 as time lords add leap second
Software could crash and markets suffer as a leap second is added to world time at midnight on June 30
By Sarah Knapton, Science Editor
1:31PM BST 29 Jun 2015
Airlines, trading floors and technology companies are braced for chaos on June 30 as world timekeepers prepare to add a leap second to global clocks.
Immediately before midnight dials will read 11:59:60 as clocks hold their breath for a second to allow the Earth’s rotation to catch up with atomic time.
When the last leap second was added in 2012 Mozilla, Reddit, Foursquare, Yelp, LinkedIn, and StumbleUpon all reported crashes and there were problems with the Linux operating system and programmes written in Java.
In Australia, more than 400 flights were grounded as the Qantas check-in system crashed.
Experts at Britain’s National Physical Laboratory (NPL) who will officially add the second to UK time, warned that markets which are already jittery from Greece could suffer transaction delays if their software was not prepared.
“There are consequences of tinkering with time,” said Peter Whibberley, Senior Research Scientist in the Time and Frequency group at NPL, who is known to colleagues as ‘The Time Lord.’
“Because leap seconds are only introduced sporadically it is difficult to implement them in computers and mistakes can cause systems to fail temporarily.
"Getting leap seconds wrong can cause loss of synchronisation in communication networks, financial systems and many other applications which rely on precise timing. Whenever a leap second occurs, some computer systems encounter problems due to glitches in the code written to handle them. The consequences are particularly severe in the Asia-Pacific region, where leap seconds occur during normal working hours."
European markets including London are largely closed when the event is scheduled to occur, but the change will hit trading floors in the US, Japan, Australia, South Korea and Singapore.
...
Atomic time is constant, but the Earth’s rotation is gradually slowing down by around two thousandths of a second per day.
Leap seconds are therefore essential to ensuring civil time does not drift away from time based on the Earth's spin. If not corrected, such a drift would eventually result in clocks showing the middle of the day occurring at night.
etc...
http://www.telegraph.co.uk/news/sci...ead-115960-as-time-lords-add-leap-second.html
Clocks to read 11:59:60 as time lords add leap second
Software could crash and markets suffer as a leap second is added to world time at midnight on June 30
By Sarah Knapton, Science Editor
1:31PM BST 29 Jun 2015
Airlines, trading floors and technology companies are braced for chaos on June 30 as world timekeepers prepare to add a leap second to global clocks.
Immediately before midnight dials will read 11:59:60 as clocks hold their breath for a second to allow the Earth’s rotation to catch up with atomic time.
When the last leap second was added in 2012 Mozilla, Reddit, Foursquare, Yelp, LinkedIn, and StumbleUpon all reported crashes and there were problems with the Linux operating system and programmes written in Java.
In Australia, more than 400 flights were grounded as the Qantas check-in system crashed.
Experts at Britain’s National Physical Laboratory (NPL) who will officially add the second to UK time, warned that markets which are already jittery from Greece could suffer transaction delays if their software was not prepared.
“There are consequences of tinkering with time,” said Peter Whibberley, Senior Research Scientist in the Time and Frequency group at NPL, who is known to colleagues as ‘The Time Lord.’
“Because leap seconds are only introduced sporadically it is difficult to implement them in computers and mistakes can cause systems to fail temporarily.
"Getting leap seconds wrong can cause loss of synchronisation in communication networks, financial systems and many other applications which rely on precise timing. Whenever a leap second occurs, some computer systems encounter problems due to glitches in the code written to handle them. The consequences are particularly severe in the Asia-Pacific region, where leap seconds occur during normal working hours."
European markets including London are largely closed when the event is scheduled to occur, but the change will hit trading floors in the US, Japan, Australia, South Korea and Singapore.
...
Atomic time is constant, but the Earth’s rotation is gradually slowing down by around two thousandths of a second per day.
Leap seconds are therefore essential to ensuring civil time does not drift away from time based on the Earth's spin. If not corrected, such a drift would eventually result in clocks showing the middle of the day occurring at night.
etc...
http://www.telegraph.co.uk/news/sci...ead-115960-as-time-lords-add-leap-second.html
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Doesn't time fly - here we go again!
New Year delayed by one second
30 December 2016
A "leap second" will be added to this year's New Year's countdown to compensate for a slowdown in the Earth's rotation.
The extra second will occur as clocks strike midnight and a time of 23:59:60 will be recorded, delaying 2017 momentarily.
A leap second last occurred in June 2015 and this will be the 27th time it has occurred.
The change is required because standard time lags behind atomic clocks.
The National Physical Laboratory (NPL) - responsible for the UK's national time scale - uses the atomic clock to provide a stable and continuous timescale.
Along with other clocks across the globe, it provides the world with its coordinated universal time.
NPL senior research scientist Peter Whibberley said: "Atomic clocks are more than a million times better at keeping time than the rotation of the Earth, which fluctuates unpredictably.
"Leap seconds are needed to prevent civil time drifting away from Earth time.
"Although the drift is small - taking around 1,000 years to accumulate a one-hour difference - if not corrected it would eventually result in clocks showing midday before sunrise."
Atomic clocks use the change of electron energy levels to tell the time.
The time created by the clocks is used in GPS location devices and is used to control the wave frequency of television broadcasts.
The International Earth Rotation and Reference Systems Service in France tracks the Earth's rotation and announces the need for a leap second.
http://www.bbc.co.uk/news/uk-38470682
New Year delayed by one second
30 December 2016
A "leap second" will be added to this year's New Year's countdown to compensate for a slowdown in the Earth's rotation.
The extra second will occur as clocks strike midnight and a time of 23:59:60 will be recorded, delaying 2017 momentarily.
A leap second last occurred in June 2015 and this will be the 27th time it has occurred.
The change is required because standard time lags behind atomic clocks.
The National Physical Laboratory (NPL) - responsible for the UK's national time scale - uses the atomic clock to provide a stable and continuous timescale.
Along with other clocks across the globe, it provides the world with its coordinated universal time.
NPL senior research scientist Peter Whibberley said: "Atomic clocks are more than a million times better at keeping time than the rotation of the Earth, which fluctuates unpredictably.
"Leap seconds are needed to prevent civil time drifting away from Earth time.
"Although the drift is small - taking around 1,000 years to accumulate a one-hour difference - if not corrected it would eventually result in clocks showing midday before sunrise."
Atomic clocks use the change of electron energy levels to tell the time.
The time created by the clocks is used in GPS location devices and is used to control the wave frequency of television broadcasts.
The International Earth Rotation and Reference Systems Service in France tracks the Earth's rotation and announces the need for a leap second.
http://www.bbc.co.uk/news/uk-38470682
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In 2020 the earth's rotation actually speeded up (ever so infinitesimally ...), raising the prospect of implementing a negative leap second.
FULL STORY: https://www.sciencealert.com/earth-...r-than-at-any-other-time-in-the-past-50-years
FULL STORY: https://www.sciencealert.com/earth-...r-than-at-any-other-time-in-the-past-50-years
An update on that;
Earth is spinning FASTER now than it was 50 years ago - and if it continues speeding up scientists may have to deduct a second from the atomic clock
https://www.dailymail.co.uk/science...nning-FASTER-50-years-ago-scientists-say.html
Earth is spinning FASTER now than it was 50 years ago - and if it continues speeding up scientists may have to deduct a second from the atomic clock
https://www.dailymail.co.uk/science...nning-FASTER-50-years-ago-scientists-say.html
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Go take a leap, foul leap second! The relevant governing body has voted to eliminate the current leap second protocol by 2035.
FULL STORY: https://www.livescience.com/goodbye-leap-second-2035
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This Scientific American article (from before the meeting / vote) explains one less-mentioned reason for deciding to eliminate the current leap second protocol:
FULL STORY: https://www.scientificamerican.com/...ime-is-up-world-votes-to-stop-pausing-clocks/